With the development of manufacturing process technologies, the present electronic apparatus is required to have a smaller circuit area and a lower operating voltage. Basically, memory is one of the devices in an electronic apparatus that consumes the majority of electrical power due to its complicated and large circuit structure and its high frequency of data reading and writing. Therefore, designing a memory consuming less power and capable of being operated at a relatively low operating voltage is a main challenge for the research and design fellows.
In general, a memory is constituted by a plurality of memory cells, a pre-charge circuit, a write circuit, a row and a column decoders and a sense-amplifier circuit, which is configured to sense the readout contents of the memory cells. However, because the operating voltage is getting lower with the development of manufacturing process technologies and thus the bit lines may have weaker input signals thereat, the sensing range of the sense-amplifier circuit accordingly plays a major role for the memory's efficiency. However, in the manufacturing process, the transistor switches in the sense-amplifier circuit may have a mismatch, so a compensation circuit is usually disposed in the sense-amplifier circuit to eliminate the mismatch effect.
Generally, the compensation circuit may be implemented by digital-to-analog converters; however some problems, such as having a higher cost, accordingly arise due to the complicated feedback control design. Or, the compensation circuit may be implemented by capacitors and switches; however some problems, such as being too sensitive and being easily affected by noise signals so as to resulting in misreading, also arise.